Sunroof tilts open on it's own ? Any ideas

[TheShark850]

Different car , so I made a different thread for it

1992 850i Manual

The sunroof buttons won't work , however the sunroof will tilt open by itself when ignition is on ? I can use the key on the door to open the sunroof and close it , but when ignition is on and key inside the ignition , it'll just tilt open again

Also I believe it's the reason my batteries are draining

Please help , thanks guys

[Timm]

Have you tried disconnecting the sunroof switch?

[TheShark850]

The one that moves it in / out / up ? Yes I have , no change , still opens by itself when ignition is on

[Timm]

The sunroof module appears to be very reliable - I can't remember instances of it causing the problems you are having. So, that leaves the usual suspect, the General Module!

[rob1210]

Have you reset the sunroof?

Remove the sunroof motor cover behind the interior dome light. Using the crank in the toolbox (in the boot/trunk) wind the sunroof all the way forward until it hits a physical stop, at which point it should be in the full tilt position. Press and hold the sunroof's tilt button for ~15sec. You should hear/see a jolt while the sunroof module creates a reference point, from which it then counts a specific number of turns rearwards to determine the full closed and open positions.

If the problem persists then, as Timm intimates, you might need to replace the 5 capacitors in the General Module.

[cartoonz]

Have you tried disconnecting the sunroof switch?

The one that moves it in / out / up ? Yes I have , no change , still opens by itself when ignition is on

Repair/Rebuild your General Module. As Timm already pointed out, the sunroof module is rather robust... and quite simple. If your sunroof is doing anything at all with the sunroof switch removed from the circuit, only the GM can be driving the 12v to the sunroof module relay (which I think is solid state, but I don't recall for sure).

There are a few other unlikely and obscure theoretical culprits that could conceivably trigger such a phenomenon, but the seemed absence of related issues would make those odds even less likely. Rebuild the GM. You'd have to do this first in order to trace any of the above mentioned freak causes anyway, but it is doubtful we'll need to even consider that after the GM is right.

[TheShark850]

The thing is.......I've already repaired the module to fix my trunk issue . I bought the capacitors from the bimmerforum guy that sells them , replaced them on both the 850s , issue is still present regarding the sunroof . Any other ideas ? I will open the module again to be safe , but I'm open to suggestions as well

[TheShark850]

Well I can close this thread - found the issue ! It was the module (?) that's on top of the headliner by the sunroof . Now the sunroof is fully functional . If anyone has non operating sunroof that tilts open on it's own - it's the sunroof motor thing next to the sunroof

BIG thanks to everyone that chimed in !

[Timm]

That's great news - although we helped we all said the sunroof module wasn't the problem!

[TheShark850]

That's great news - although we helped we all said the sunroof module wasn't the problem!

It's okay . It's good to repair the general module if it never has been , it'll likely go out , but since I did repair it before and the issue was still there , I had to dive in deeper . I'm blessed??? to have two 850s and interchanging parts to figure out the issues of them . For anyone who has one , this would of been a PAIN , time consuming and costly . I interchanged the general modules as you guys stated (in case I made a mistake) and found out that they're both good as my problem didn't get fixed , then I changed the sunroof module and it got fixed . If I didn't have a spare , I would of been very VERY hesitant to shell out $200+ for a used one on ebay in hopes that's the issue